The present invention relates to surgical instruments, with examples relating to cardiovascular pacing devices, systems for controlling such devices, and methods for using such devices. “Surgery” generally refers to the diagnosis or treatment of injury, deformity, disease, or other conditions. In a variety of surgical procedures, it may be desirable to stimulate the heart using a pulsed current via a bi-polar probe or other device. Such pacing may be desirable, for instance, after an ablation procedure has been performed on a heart in order to determine how successful the ablation was. Accordingly, it may be desirable to provide a device operable for use in both ablation and pacing procedures. The foregoing examples are merely illustrative and not exhaustive. While a variety of devices have been used to pace the heart of a patient or perform other procedures, it is believed that no one prior to the inventors has previously made or used an invention as described in the appended claims.
The present invention relates to surgical instruments, with examples relating to bi-polar ablation devices in combination with a variety of sensors, systems useable with such devices, and methods of using such devices. Surgery generally refers to the diagnosis or treatment of injury, deformity, or disease. In a variety of surgical procedures, it is desired to ablate tissue or cause lesions in tissue. Some examples of such procedures include, without limitation, electrical isolation of cardiac tissue to treat atrial fibrillation, ablation of uterine tissue associated with endometriosis, ablation of esophageal tissue associated with Barrett's esophagus, ablation of cancerous liver tissue, and the like. The foregoing examples are merely illustrative and not exhaustive.
Atrial fibrillation is an abnormality of the electrical system of the heart. Normally, the heartbeat is triggered by an electrical impulse which starts in the Sinoatrial (SA) node structure which resides in the right atrium and acts as the “pacemaker” of the heart. The electrical signal to contract the heart starts in the SA node and normally moves evenly across the atrium, triggering it to contract all at once. The impulse then travels across the atrioventricular (AV) node and triggers the ventricles (the main pumping chambers of the heart) to contract. This is called sinus rhythm. Atrial fibrillation occurs when this electrical impulse no longer travels in the normal manner and causes the atrium to contract in an un-coordinated manner, causing irregular fibrillation. The MAZE Procedure is a surgical procedure used by Cardiothoracic surgeons to create scar tissue barriers in the heart as a way to block the unwanted electrical signals that cause erratic heartbeats or atrial fibrillation. By way of example, this procedure can be performed by surgical incision and suturing, a cryosurgical system, or energy ablation devices such as a monopolar pen with saline, or a bipolar pen. The Maze procedure has been widely accepted as the gold standard of care in the treatment of atrial fibrillation with a very high success rate. This surgical procedure can be performed openly, as a minimally invasive procedure or in a modified form such as the Mini Maze procedure. The MAZE or MINI MAZE surgical procedure using an electrosurgical device begins with a voltage mapping procedure that uses a pair of tissue contact electrodes attached to a sensor such as an echogram machine to map the location of natural electrical signals that stimulate the heart to beat. Once the location of the impulses are found and mapped, the surgeon replaces the echogram machine and sensing electrodes with a pair of pacing electrodes. The pacing electrodes are held spaced apart a preset distance and are placed into contact with tissue at a number of the mapped positions. At each position the pacing electrodes are energized to stimulate the heart. If no response occurs, the voltage is increased, and the stimulation is resupplied until the heart reacts. This determines the stimulation threshold voltage at each site. The stimulation locations, stimulation responses, and threshold voltages are noted on the heart map and are used to identify the location of the specific nerves that are responsible for the irregular heartbeat. Once the heart has been mapped, the pacing electrodes are removed and replaced with one or more electrosurgical devices that apply RF energy to the heart to create lesions therein. RF energy is applied via the electrodes to create one or more coagulated lesions on the heart. The ablation electrodes can also be used to monitor tissue effects such as impedance during ablation. After the lesions of cauterized tissue are placed onto the heart, the electrosurgical device or devices are removed. The efficacy of the lesion is sensed by placing the pair of echogram electrodes across or onto the lesion area to sense continuity across the lesion. If there is no continuity across the lesion, the lesion was successful. Alternately, or in addition to the echogram electrodes, the pair of pacing electrodes can be placed across the lesions to apply stimulation voltages. These stimulation voltages can also be used as an alternate check of the efficacy of the lesion. If the stimulation voltages fail to stimulate across the lesions, the lesion was successful.
At present, there are no known electrosurgical instruments that can meet all of the needs outlined above. These and other advantages will become more apparent from the following detailed description and drawings